Amateur radio, space technology and other geeky stuff by Alexandru Csete
Hardware experiments by Alexandru Csete OZ9AEC.
At long last, I have found some time to start playing with Arduino stuff!
I decided that good starter project would be simple weather station that reads temperature, pressure, … sensors and shows them on an LCD display. Below you will see a first cut using a TMP102 temperature sensor from Texas Instruments mounted on a breakout board from Sparkfun.
The WM-2 from Oak Hills Research is a cool QRP wattmeter kit, which can measure forward and reflected power in three ranges: 100mW, 1W and 10W. With an accuracy of 5% of the full scale it should be possible to measure powers down to 5mW using this instrument. The WM-2 has a big, easy to read scale and can operate either from a built-in 9V battery or an external DC source.
Now that my OHW WM-2 is assembled, it is time to align it. The manual has detailed step by step instructions on this as well and the alignment procedure is relatively straight forward. On the other hand, adjusting the potentiometers can be a little difficult, partly because some of them are hidden below the wires and partly because R6 has to be adjusted with a precision of 1 mV while it has a full scale of several volts. It would have been very nice with a multi-turn potentiometer instead.
I’m continuing with the connectors switches and the instruments. I don’t quite understand why the assembly manual wants me to use the bottom row on the power switch instead of the top row. The switch is already mounted on the cabinet and thus the bottom row is much more difficult to access than the top row. I just ignore this step and use the top row.
I made further progress with the wattmeter tonight. It was time to prepare the wires, which consisted of cutting them to various lengths and removing the isolation at the ends. Here I faced the first difficulty in trying to follow the instructions of the manual.
I have now received the three 1N34A diodes that were missing from the OHR wattmeter kit and tonight I resumed the assembly.
I just finished mounting all the resistors when I noticed that the three 1N34 diodes are missing from the component bag. Well, I guess I won’t finish the OHR WM-2 this weekend 😛
Today I’ll start to assemble the OHR WM-2 QRP wattmeter from Oak Hills Research. I bought the wattmeter via the German QRP Project few weeks ago but I didn’t really have time to build it yet.
The Elecraft T1 is a stand-alone, miniature antenna tuner unit specially designed for use with low-power HF/6m transceivers. Despite its small size, it uses a built in 9V battery, provides a wide matching range and can handle powers up to 20 watts SSB/CW or 10 watts in FM/AM/digi. It is a very cool general-purpose ATU for mobile and portable use. The T1 is available either ready built or as a kit.
Tonight I have tried to use the FT-817 remote cable that I bought together with the T1. First, I wanted to find the leaked RF info signals sent by the T1. According to the manual, there should be at least one signal on every ham band and I found one around 7024 kHz.